This invention relates to the field of portable painting equipment, more particularly to portable paint guns referred to as high volume low pressure or HVLP type paint guns. The invention specifically concerns an air seal for an axially movable control shaft extending through a housing of the paint gun. The present invention achieves a nearly airtight seal between the shaft and the seal and between the seal and the spray gun housing. In addition, the seal can accommodate a certain amount of radial misalignment without impairing the sealing function.
In the past, a bushing (which was not designed to be) was used to guide the shaft in its axial motion. Such a bushing allowed a substantial air flow along the shaft, degrading gun performance and, in some cases, allowing a tactilely perceptible (and thus objectionable) flow to impinge on an operator's hand. The present invention overcomes these disadvantages of the prior art while continuing to provide the guiding function.